In the natural gas industry, samples of the natural gas product are frequently extracted from a source for testing such things as the constituents and Btu value of the natural gas. Natural gas, even though generally referred to as gas, when being transported, may contain both liquid and gas hydrocarbon components. Oftentimes, a monitoring instrument such as a gas chromatograph is mounted on or connected to a conduit transporting the natural gas. It is desired to separate the liquid component from the gaseous component because many instruments will not accept the liquid component and still function properly. As seen in FIG. 1, an exemplary prior art device for connecting a sampling instrument to the conduit is illustrated and the parts are identified therein. The prior art apparatus includes various connectors, tubing and valves connecting a body with a liquid eliminator to a pipeline or other natural gas source. The body includes a cap and a base connected together. A sample is extracted through an intake and conducted through various connectors and other plumbing devices including a separate but attached inlet valve that is operable for selectively permitting flow into an inlet of the body. The sample transfers from the body inlet to a chamber and to a liquid separator such as a porous membrane backed by a support screen. The gaseous component transfers from the chamber to an instrument through the separator. The membrane allows gaseous components to pass through but not liquid components. The separated liquid is collected in the chamber and exhausted through a body outlet through various plumbing devices such as an outlet valve, connectors, tubing and flare fittings as well as an exhaust for discharge back into the conduit.
As can be seen, the prior art liquid eliminator and plumbing is complex, provides many joints each with a potential for leaking and requires separate valves. While the prior art liquid eliminators are somewhat effective, they do pose the above problems. A prior art liquid eliminator of the type shown in FIG. 1 is a model LE-2 from Welker Engineering of Sugar Land, Tex. In addition to the aforementioned problems, prior art liquid eliminators utilize relatively expensive valves which are separate from the liquid eliminator and attached thereto through various connectors and plumbing devices. Typically, such valves are made of stainless steel. An example of such a valve is a model NV-1 from Welker Engineering.
In view of the problems with the prior art devices, there is a need for a liquid eliminator apparatus that allows the integration of the various components and the elimination of many of the plumbing components to provide a simplified and more reliable liquid eliminator.
The present invention provides such an integrated structure.
The present invention provides for a liquid eliminator usable with a sampling device for extracting samples from a source of natural gas. The device includes a body with an inlet and first and second outlets. A connector portion on the body in one form is adapted for connecting the body directly to a fitting portion of a conduit, e.g., a pipleine or the like in which natural gas is contained. The body has a flow passage connecting the inlet in flow communication with the first and second outlets. First and second shut off valve assemblies are mounted in the body with the first valve assembly cooperating with the flow passage downstream of the inlet and upstream of the first and second outlets and is operable to selectively permit and prevent flow from the inlet to the first and second outlets. The second valve assembly cooperates with the flow passage upstream of the second outlet and is operable to selectively permit and prevent flow into and out of the second outlet. A separator is positioned, flow wise, between the first valve assembly and the first outlet. The separator is operable to separate liquid from a fluid in the flow passage preventing liquid from flowing out of the first outlet and for discharge from the body through the second outlet.